On my Prius III with the JBL headunit, the specs show that it comes with a 90 day trial subscription. However, I do not have the navigation system. Someone told me that only the navigation-equipped cars contain the necessary hardware to be XM ready. However, I am not sure if this is true. Does my car, given its current configuration (just JBL headunit, no navigation), have all of the hardware necessary for XM Satellite Radio? Thanks.